96GB of unified RAM. How much of that is available to the graphics cores? I haven't tested a later model but the M1 Max would max out at 16GB VRAM regardless of how much the machine had.
There's a reason companies are setting up clusters of A100s, not MacBooks.
Not only that but Apple's ram is 0.5TB/s pretty much, a 4090 gets 1TB/s. I feel like the discrete card is the better value proposition because: nobody should need to be running 80GB models on a laptop, I feel this is more in the high perf/research area, you could argue that it could be a useful tool as a co-pilot but you've tuned your machine to use all ram for the model...you can't do anything else. Additionally, it's such a specific use case for the machine that trying to sell it would be hard, whereas I can hock off a GPU to someone doing data, ML, gaming, video editing, etc.
There's a reason companies are setting up clusters of A100s, not MacBooks.